"If there is a Do Not Knock sign on the door, they do not knock and that's it," Town Supervisor Kate Murray said at a news conference Monday at the Levittown home of Margaret and Edward Tardibuono. "And if they don't [respect it], they face a $500 penalty."

The couple, both retirees, have lived in their Sheep Lane house for 40 years. Only recently have they noticed an uptick in the number of door-to-door salespeople, with four to five coming to the house in the past couple of months, Margaret Tardibuono said.

Currently, the town prohibits salespeople from knocking on the doors of residents who have posted "No Soliciting" signs.

Under the new proposal, fines for solicitors who disregard "Do Not Knock" signs on residences would increase to $500 per violation from $250. Subsequent violations would result in a $1,000 fine. Solicitors who operate without a town permit would be subject to an additional $500 fine, up from $250. The law would not affect political organizations or nonprofits such as Girl Scouts selling cookies, Murray said.

The decals -- vinyl window clings that measure 3 inches by 7 inches and display the words "Do Not Knock" and "No Peddlers" -- are designed to discourage unwanted solicitors. Murray said the town put in an initial order of 20,000 to 30,000 decals, anticipating a lot of interest in the program.

"It affects us all," she said, adding that solicitors "always seem to have a radar accuracy to knock when you're just sitting down to dinner or you're in the middle of something that really requires your attention."

Murray said in an interview she's heard support for the proposal from every demographic -- particularly from senior citizens but also from young parents and professionals.

Residents who encounter violators should call their police precinct or the town, and an officer or building inspector will respond, town spokesman Mike Deery said.

Nassau County police spokesman Insp. Kenneth Lack said officers will respond to enforce the local ordinance just as they would a state or federal law.